Surface finishing apparatus



July 3, 1956 A. s. MCGIBBON SURFACE FINISHING APPARATUS Filed May 27', 1952 7 Sheets-Sheet 1 3nnentor Gttomegs y 3, 1956 A. s. M GIBBON SURFACE FINISHING APPARATUS 7 Sheets-Sheet 2 Filed May 27, 1952 attorney- July 3, 1956 A. s. M GIBBON SURFACE FINISHING APPAR/TUS 7 Sheets-Sheet 3 Filed May 27, 1952 attorney;

July 3, 1956 A. s. MCGIBBON 2,75 ,73

SURFACE FINISHING APPARATUS Filed May 27, 1952 7 Sheets-Sheet 4 y 3, 1956 A. s. MCGIBBON 2,752,734

SURFACE FINISHING APPARATUS Filed May .27, 1952 1 Sheets-Sheet 5 2,752,734 SURFACE FINISHING APPARATUS Archie S. McGibbon, Steel Company, sylvania Thorndale,

Pa., assignor to Lukens Coatesville,

Pa., a corporation of Pennparticularly concerned with apparatus having rotatable means for performing the operation, for example a rotatable endless belt for the finishing of a work piece such as a large piece of steel plate.

The invention is of special advantage and utility in manufacturing plants, for instance for the finishing operation in the manufacture of steel, alloy steels, clads or other metals in plate form.

The apparatus of the present invention is particularly adaptable in those cases where accurate and rapid surface conditioning such as grinding or polishing must be maintained in a schedule requiring high rates of production.

One of the objects of the invention is to provide in a machine for the surface conditioning of a Work piece an endless rotatable belt which is capable of tilting motion with respect to the surface of the work piece whereby to permit desired finishing characteristics even where the work surface contour is uneven or irregular.

Another object of the invention is to provide in a machine for the surface conditioning of a work piece an endless rotatable belt which is universally movable relative to the surface of the work piece while being capable of tilting motion with respect to the surface of the work piece whereby to permit the desired finishing characteristics, even where the work surface contour is uneven or irregular.

Another object of the invention is to provide in a machine for the surface conditioning of a work piece an endless rotatable belt which is adapted to be shifted or oscillated in a direction along its axis of rotation whereby to enable the finshing of a Work piece without graining or scarring of the surface due to chips and the like, the shifting motion being independent of the rotary and tilting motions.

Another object of the invention is to provide in a machine for the surface conditioning of a work piece an endless rotatable belt and apparatus for the support thereof which maintains a substantially constant preselected engagement pressure between the belt and the work piece.

The novelty and utility of the present invention together with certain other features and objects will be readily apparent from the following description and drawings:

Figure l is an elevational View of a machine constructed in accordance with my invention with the lower portion of the view appearing in section;

Figure 2 is a fragmentary plan view of Figure 1;

Figure 3 is an enlarged sectional end view of the machine taken substantially on the line 33 of Figure 4 with certain of the cantilever and trunnion structure appearing in dot and dash lines;

Figure 4 is a sectional elevational view taken substantially on the line 4-4 of Figure 3;

Figure 5 a fragmentary cross sectional view of belt 2,752,734 Patented July 3, 1956 tightener-release mechanism employed in the machine, the section being taken on the line 55 of Figure 6;

Figure 6 is a section taken on the line 6-6 of Figure 5;

Figure 7 is a plan view of an element of the mechanism of Figures 5 and 6;

Figure 8 is an enlarged fragmentary plan view of shifting mechanism for the top roll of the machine;

Figure 9 is a cross sectional view taken on the line 99 of Figure 4 and illustrating trunnion mechanism of the machine;

Figure 10 is a plan view of Figure 9;

*igure 11 is a diagrammatic view of the hydraulic system of the machine;

Figure 12 is a block electrical diagram; and

Figure 13 is a schematic diagram of the system to operate the belt oscillating mechanism.

Referring first to Figures 1 and 2, the general arrangement of the equipment of the present invention Will be described.

A work piece such as the plate W is mounted on a bed generally indicated by the reference numeral 1. In the preferred form, the bed 1 is constructed of solid material such as concrete 1a, in which are embedded a plurality of l-beams 11) disposed transversely and serially extending throughout the length of the bed. On the top part of the l-beams lb a plurality of abutting plates 2 are secured as by bolts 3. The bolts 3 are countersunk in the plates 2 and are easily removable to accommodate attachment of clamps t, which secure the Work piece W to the bed. Certain other threaded holes such as holes 3a may be provided in plates 2 for desirably accommodating clamps 4. As will be apparent from an inspection of Figure 2, the clamps 4 may be desirably positioned on the plates 2 so as to accommodate work pieces of varying sizes and shapes.

Located on each side of the bed are recesses 5, which extend throughout the length of the bed. As is seen in Figure 1, the concrete portion of the bed is slightly tapered from the center section out to the recesses 5. This construction leaves certain space between the top part of the concrete and the plates 2 and is used in certain instances for equipment adapted to circulate a coolant medium where operating conditions require cooling of the work piece.

The l-beams 6 are secured at the bottom of the recesses 5 and extend throughout the length of the bed. On the top of the I-beams 6 are secured tracks 7 having a V-shaped top section which accommodates the V-shaped grooves in the wheels 8. The wheels 8 are connected to the bridge member generally indicated by the reference numeral 9 to provide for the movement of the bridge 9 over the length of the bed.

As best seen in Figure 2, the bridge member 9 is generally rectangular in shape and is ordinarily constructed of l-beams which are welded together and braced with certain structural members. The power to drive the bridge to and fro over the bed is provided by electric motors l0-10, which are appropriately secured to the bridge. The motors operate through gear boxes it to rotate the shafts 12, which are keyed to the wheels 8.

Secured to the top of the bridge 9 are tracks 13, WlliCl'l extend in a direction at right angles to the direction of movement of the bridge. The tracks 13 are V-shaped on the topmost portion to accommodate the V-shaped grooves in the wheels 14 and 15. The wheels 14 and 15 are secured to trolley member 16 and provide for mobility of this unit in a direction at right angles to the direction of movement of the bridge 9. The trolley 16 is comprised essentially of two structural members 15a and 16b, which extend in the same direction as tracks 13 and to which the wheels 14 and 15 are rotatably secured. Deck plate 16c connects the structural members ltia and 16b together. Motive power for the trolley is supplied by electric motor 17. The motor, acting through gear box 18, drives shaft 19, which is keyed to wheels-14-14.

With the above-describedarrangement, it may be seen that, by appropriately controlling the-operation-of electric motors 10ltl and electric motor 17 ,-the trolley member 16 may be universally moved' over the-bed 1. It is to be observed that the tracks =13 extend on one side in a direction somewhat outside of the immediate area of the bed ll. This extension accommodates trolley movement somewhat outside'of the area of the bedso that the belt may be moved all the way over to the right sideof'the bed (see Figure l).

Secured to the deck plate 160 is a cantilever structure generally indicated by the reference numeral -20. At the unsupported end-of thecantilevor is located a trunnion arrangement 21 whose axis is parallel to the bed surface and extends in the same direction as tracks '7. Upright members 40 and 41*are rigidly connected together by the plates 115-115 of trunnionZl and-by the tubular brackets TIM-115a (see Figures 3, and 6). The trunnion supports the upright members and :provides for tilting of the belt and belt mounting structure :in a manner'to be described more in detail hereinafter. The'belt is indicated by the reference numeral-23 and is rotatably mounted on certain rollers 36, 37, 38 and 39 (Figure 3), which are supported by suitable bearings on upright members 4-0 and 41.

As will be readily apparent from the foregoing description, the belt 23, beingmounted on the universally movable trolley, is universally movable over the area of the bed, hence, is universally movable overthe surface of a work piece secured to the bed regardless of the size or shape of the work piece. It isto-be observed that this universal movement is independent both of the rotation of the belt and of the swinging motion of the belt.

Also mounted on the trolley deck plate 16c is belt drive motor 24, whichopera'tes shaft 25 and pulley 26, which act to rotate the belt in a manner more fully described hereinafter.

The pump motor27 is'ada'pted 'to operate hydraulic pump 28, which is used to buildup pressure for certain of the hydraulic control mechanisms to be laterdescribed.

The control panel-29 is also'secured to' the'trolley deck plate 160. The rheostat'fifl, slhown o'n' the left-hand side of the control panel 29, is used to control the speed of the belt drive motor 24, and the meter-31 is used to indicate the current being drawn by the motor 24. The push buttons 3-2 are used to operatecertaincontrol mechanism for stopping and starting the belt'drive motor 24. The push buttons33 control the operation 'of thepurnp motor 27. The push buttons-fluctuate certaincontrol mechanism for the bridge-motors' lti l-ti; the upper two buttons being for forward ahd' reverse motion and the lower button for stopping the-bridge. The push buttons 35 actuate certain control mechanism fortlie trolley-flame upper two buttons being for forward and reverse motion and the lower button for stopping the'troll'ey. The operating levers 125a, 132a and 1330 'are for actuating certain control valves in the hydraulic system to be later described.

Somewhat diagrammaticallys'h'own on Figure 2 are two photoelectric cells 42 and 43, which are oppositely disposed with reference to one 'edge'of belti3. These cells develop certain signals depending upon the'po'sition of the belt with respect'to' the light beamsassociafedwith the cells. The signals are utilized to actuate-certain control mechanism associated with roller 36, which pivots the axis of the roller about one of the bearings. The roller, being pivotally shifted obliquely to the path of rotation of the belt, tends to shift or oscillate the belt back and forth along the axes of the rollers. Thisoscillating-movement of the belt is independent of belt rotation and also independent of both the universal movement and swinging movement of the belt.

Having described the general arrangement of the equipment of the present invention, certain components of the apparatus will be described in detail following.

The structural details of the belt mounting structure 22 are seen in Figures 3 and-4. The belt 23 is rotatably mounted onrollers 36, 37, 38 and39. T he axes or shafts of the rollers are substantially parallel to one another and are located generally at the vertices'of a parallelepiped. The shafts of the rollers are supported betweeni'the upright members 40 and 41 by certain structural members.

The shaft 37a of drive roller 37 'is supported at each end in bearings 44-44 secured to angle-bar members 45-45 respectively attach'etlto upright members 40 and 41.. The roller 37 is adapted to be driven by the belt drive motor 2 5. For this purpose, as seen in Figure 4, a-pulley dis-attachedto one end of the shaft 3%. The pulley may beigroov-ed to accommodate-multiple your 47-, which also engages a pulley .26, which is'seoured to shaft 25 of belt motor "24. TheshaftZS is rotatably mounted in bearings 4848, which are supported by members 49-49, secured to upright-meinbersltl and. The outer surface 37b of roller 37*is providedwitlrsuitable material, for example, rubber -.or -rubbe'r-like toomposition, so as to promote a driving engagement ofthc roller surface and the inside area of theme/1623.

It is to-be-observedthat the shaftZS is-provided'with-universal joints 25a-25a, which: accommodate. tilting of the beltand belt mounting structure while the-belt-is being rotated. The details of this tilting movement -will be described in detail hereinafter.

The =idler roller 38, in addition to serving-at rotatable mounting means for the beltu23,-is -also utilizedto-tighten the belt as itis mountedon the-rollers and-also to loosen the belt so as to permit removal 'ofthesame-from the mounting structure.

With particular reference to Figures 3, .5 audfi, it is seen that the shaft 38a of theroller 38 is rotatably-supported at each en'd'by bearings 50-50; which are fixedly secured to brackets 51-51. The brackets S l -51 Pare provided withholes-accommodating pins-52-524and are f xedly secured to .pins-52+52-as--byset-screws53 53. The pins 52*52 are rotatably supported i-nbearings 5- 3-4, which are respectively secured to uprighbm-embers 4i and 41. The inboard portions of pins-52--52 are fixed to respective ends oft-shaped--crank--nrembers 55-55. The centersectionsof-the L-shapedcrankmembers Sh -55 are connected together by urod 56. The downwardly-extending portions: of the -t;-shaped crank members s-55 (Figure 5) are provided with holes which accommodate pins 57*51 engaging the head portions of thepiston rods -58-58of hydraulic -cylinders 59-59.

The hydraulic cylinders are pivotallyattached to upright members The operation or 40 and 41 as by tpivots-60.60.

release mechanism is as the above-described belt tightenerfo llowszfwhen' hydraulic fluid is applied to the hydraulic cylinders 59 59, for example, through fluid-line 59a, thepisto'n rods5858 move upwardly,which pushes thet-shap'ed Ci'arikme'mbErsSS SS upwardly. Since the cranks-are fix'e'dto' pins "52 5'2, the cranks' rotate the pins. Rdtation of the 'pin's S2 52 also rotates the members 5'i-'5 1,=-lrence, rotates the "supporting bearings 'SQJS'QQHGTOHET SSin -anarcuate path. The ends of roller shaft iiSa :move inwardly through theslots 61-6l in upright members40- and-41. Fhusnvhenithe roller is moved inwardlyfrom its wnormalfiposition as shown-in fiigure 3, -the beltisloosenedon its mountand may be: removed.

. When hydraulic'pressure -is-=applied to the top ;-part 'of cylinders 55 through dines 59!), the :fipistontrods 58-58-are moved-downwardly, and the shaft 38a of'the roller is accordingly moved 'outwardly tin-slots 61- 61. Thus,- by -supplying appropriate"hydrau-lic pressure' tto the cylinders 59S9, the roller 38 may be moved outwardly 5 to supply desired tension on the belt. The hydraulic system for activating the cylinders 59-59 will be described more in detail hereinafter.

It is to be observed that the roller 38 is equipped with a resilient surface 38]), for example, of rubber or rubber composition or the like. This is preferably softer and/or thicker than the friction surfacing 37b of the drive roller 37 so as to reduce the noise level produced by the rotation of the belt and the roller, while at the same time, the frictional nature of surfacing 38b, by avoidig slippage between the roller and the belt, tends to maintain uniformity of any chosen belt operating speed by virtue of the fly-wheel eifect of the mass of the roller 38.

As has been mentioned heretofore, the contact roller 39 and the control roller 36 are mounted to be simultaneously moved upwardly and downwardly to engage the belt with the surface of the work piece. The mechanism for moving these rollers will be described following.

As is seen in Figures 3 and 4, the shaft 36:! of roller 36 is supported by bearings 62 and 63, respectively secured to operating arms 64 and 65, which are pivotally mounted on upright members 41 and 40 by pivots 66-66. Secured to the lower side or" the operating arms 64 and 65 are bearings 67-67, which rotatably support rod 68. Inner bearings 69-69 are mounted on bushings 70-70, which are secured to the rod 68. The downwardly extending rods 71-71 are connected to bearings 72-72, which are mounted on bushings 73-73 secured to rod 74. The rod 74 is rotatably supported at each end by bearings 75-75, which are secured to operating arms 76-76, pivotally mounted on upright members 4% and 41 by pivots 77-77. The bearings 83-83 are secured to the bottom of operating arms 76-76 to rotatably support the shaft 39a of roller 39.

Thus, it is apparent that by means of the above-described structure, the rollers 38 and 39 are arranged so as The rods 71-71 are provided with triangular-shaped members 78-78 (Figure 3), which are pivotally attached to the operating heads 7941-7901 on piston rods 79-79 of belt pressure control cylinders 80-80. These working pressure cylinders are pivotally attached to upright members 46 and 41 as by pivots 81-81. When hydraulie fluid is supplied to the bottom of the cylinders hit-8'!) as by fiuid lines title-80a, the operating head 7% is moved upwardly to move upwardly the rods 71-71, hence, the operating arms and the rollers 36 and 39. The slots 82-82, provided in upright members 49 and 41, accommodate arcuate movement of rods 68 and 74, about the pivots 66 and 77 of the arms 64 and 76, which carry the rollers. When hydraulic pressure is supplied to the cylinders fill-80 through lines 8tlb-8iib, the rollers are adapted to be moved downwardly. The 11 draulic system for activating the cylinders 80-853 and the manner in which constant work engagement pressure is maintained will be explained more in detail hereinafter. The ultimate downward travel of the rollers may be adjustably limited by the screws 34-84 operated in the nuts 85-85 respectively secured to the upright members 4% and 41, thus preventing excessive drop of the rollerand-belt assembly as it moves off the edge of the work piece.

The roller 39 is equipped with a resilient surface 3%, such as rubber or rubber composition or the like similar to that used on roller 38. In addition to the advantages mentioned in connection with the description of roller 38, the resilient material on roller 39 prevents damage to the surface of the work piece that might be caused if an unyielding roller surface were to point. Actual tests show that the cushioned roller 39 in combination with the trunnion mounting of the assembly minimizes defects and irregularities in the finishing operapiece itself has irregularities and 63. The bearing 62, 111 addition to iotatably supporting the axis 36a,

This pivoting motion is accomplished by horizontal movement of bearing 63 along the top surface 64a of operating arm 64 (Figure 3). The bearing 63 is slidably attached to the surface 64a of the operating arm by bolts 36-36. As seen in Figure 8, the bearing 63 is provided with slots 87-87, through which the bolts 86-86 extend. One end of the bearing 63 is extended to form an arm provided with a vertical slot 88, which is adapted to engage the cylindrical operating head 89 of lever 90. The lever 90 is pivotally secured to the o erating arm 64 as by pivot 91. The lower end of the lever 90 is pivoted to the operating head 92 on piston rod 93 of hydraulic cylinder 94, which is pivotally mounted on triangular-shaped member 95 by pivot 96. The triangular-shaped member 95 is fixedly secured to the underside of the operating arm 64. Hydraulic fluid is adapted to be supplied to the hydraulic cylinder 94 through lines 94:: and 94/) at alternately predominating the piston rod 93 63 back and forth on its seat 64a.

Pivotally moving one end of shaft 36a and thus one end of the roller 36 as above-described, moves the roller obliquely to the path of rotation of the belt. When the roller is thus skewed to the path of rotation of the belt moved back and forth.

The general arrangement of the photoelectric units 42 and 43, which control the supply of fluid under pressure to the lines 94a and 9% on hydraulic cylinder 94, is shown on Figures 2 and 3. Portions 42a and 43:: contain the light sensitive element for each unit, while 42b and 43b contain the light sources for the units. These units are secured to upright member 41, so that when the belt is centered on the rollers, the light beam for unit 42 is intercepted by the belt; whereas, the light beam for unit 43 is not intercepted.

diagram shown on Figure 13.

as such circuits are well-known to those skilled in the art of photoelectric controls. Contacts LR-1 and RR-l are associated with the respective relays LR and RR and are adapted to be closed when the relays are energized. Closing of the LR-l and R -1 contacts supplies power to a second control relay M. When the control relay M is energized, the holding contacts M-3 close, together with the control contacts M-1 and control contacts M-1 and M-2 supplies power from terminal P-l-P-Z to the valve solenoid S, which is adapted to operate certain of the fluid ports associated with the valve 102.

The operation of the valve 102 is as is de-energized, the ports 103 and M-2. Closing of the 04 are interconnected so that the high pressure fluid from pump line 107 is supplied to the left side of the cylinder "9'4 through line 94a. Ports 1455 and 1&6 .are also interconnected to-conn'ect'the 'other side of the cylinder94'to sump via line 94b and 103. With high pressure supplied in the left side of the cylinder, the piston rod is moved to the right. This moves bearing 63 to the left (as viewed in Figure 3), shifting the roller 36 obliquely to the'rotational path of the belt so that the'belt is caused to travel over toward the right (as viewed in Figure 2), assuming that the belt is passing over said roller in the direction of the arrow shown thereon in Figure 2.

'When the control solenoid S becomes energized, the above-describedconnections -are broken and the ports 1'03 and 105 are interconnected so that the higher pressure fluid from pump line 1'87 is supplied to the right side of the cylinder via line 94b. Ports "194 and 106 are also interconnected so that the left side of the cylinder is conncctedto sump via lines 940 and 108. With pressure on the right side of the cylinder, the piston rod93 moves toward the left. This moves the roller 36 obliquely to the rotational path of the belt oppositely tothe movement previously described, so that the belt is now caused to move toward the left.

Theoperation of the arrangement is as follows: When the belt is in the position as shown on Figure 2, the light sensitive element in phototube 43a receives maximum intensity and the phototube current acts to reduce the negative bias on amplifier tube 101 to permit the tube to conduct and energize relay RR. The light sensitive element inphototubed-Za, receiving no light from its source, has no effect on the bias 'on tube 100, so that the tube is non-conductive and the relay LR is not energized. When therelay RR is energized, the RR-l contacts close. The LR-1 contacts being open, no power is supplied to the control relay M so that the control solenoid S is not energized. As has been mentioned above, whenthe control solenoid S is energized, fluid is supplied to the righthand end-of hydraulic cylinder 94 so thatthe belt moves toward the left side. When the edge of the belt has moved far enough to the left to permit'the light sensitive element in phototube 42a to receive light, the LR relay is energized and the LR-l contacts close. Since the RR- lcontacts are already closed, power is then supplied to the control relay M to pick up the holding contact M-3 and control contactsM-1 and M4. Power is then supplied to the control solenoid S, which acts to supply the-higher fluid pressure to the left 'end of the hydraulic cylinder 94 to move the belt to the right. moves far enough to the right so that the light falling on the light sensitive element in phototube 42a is interrupted, the control relay LR is then tie-energized and the LR-l contacts open up. The'control relay M remains energized, however, through the RR-1 contacts, and the X holding contacts M-3. The belt continues to move toward the right until such time as the light falling on the light sensitive element in phototube ida is interrupted. This acts to de-energize the relay RR, which opens up contacts 'RR1 to de-energize the control relay M and thus, the control solenoid S. With the S solenoid dee'nergized, the fluid-pressure to the cylinder94 is reversed and-the belt is again moved toward the left.

fMoving the belt back and forth as above described performs two functions. The first function is to keep the belt on'the rollers. For example, if the roller 36 is skewed so that the bearing 63 is in position forward of its normal center position, the'belt (travelling in the direction of the arrow in'Figure '2) *will move to'the left and tend to move off the rollers in that direction. However, afterja-n inch or two of such movement (the amount depe'riding upon the-location andtirnin'g of the circuitsand mechanism just described), the roller is skewed to .an opposite angle, i.-e.,-w ithits bearing 63 rearward of its normal' center. position, -and the "belt'w'illthen tend to When the belt travel odthe rollers toward the right-until again reversed. Thus, bypivoting "er skewing the rolleranis "forward and rearward of the normal center position, the belt may be made to move-back'and forth over the-rollers ina manner so as to prevent the belt "from slipping off the assembly.

The other function performed by the above-described oscillating movement of the belt is to prevent certain damage to the workpiece caused by -chips or the like which maybe undesirably-presentbetween the work surface and the belt. The oscillating movement o'f-th'e' belt tends to throw out such chips, and, in any instance where a chip is not so thrown out or removed from the Work surface, the oscillation prevents -a (ship frommaking a noticeable straight line grain on the Wonk surface.

It will be observed that the oscillating me'tal 'drurn roller 36 is not provided with-a 'fr-ictional surfacing material, as I find that the smooth surface thereof is conducive to easy oscillationand is yet entirely adequate'to cause the belt to progress gradually from side to side in accordance with the obliquity of-position of the roller.

The details of the cantilever'and trunnion arrangement which permit tilting of "the whole polishing head assembly will now be described.

As seen-in Figures 4 and '10, the cantilever 20 is-secured to the trolley deck plate 16c, as by means of bolts I09. Downwardly 'extending brackets 11 0-11 0 are secured to the unsupported end of the cantilever as by welding. Trunnion shafts 111-111 Figure'9) are fixedly secured to the lower portions of brackets 110. Disposed around the shafts are sleeves 112-112., at the ends of which are the inner races of the bearings I113-113. The bearings 1'13-113rotatably support-the outer trunnion housings 1 14-114. The housings are secured to the heavy cross-plates 11511'5, which (as -hereinbefore mentioned) interconnect the upright members 40 and 41, which carry the rollers and the belt.

By means of the above-described arrangement, the belt mounting structure 22, hence the belt .23, being carried by the trunnion arrangement, has freedom for lateral tilting movement. The structure is arranged so thattheshafts 111 -111,forming"the axis of the'trunnion, are mounted substantially parallel to the'plates 2. secured to bed 1 so that the tilting motion takes place in a plane substantially perpendicular to the surface of the bed 'or work piece.

The angular postion 'of the belt mounting .structure about the trunnion axis 'is -determined or affected by resilient means, which preferably takes the form of springs. mounting structure and belt about the trunnion axis, that is to say, tends to center the arrangement in an upright position, i. e., with the axes of the rollers horizontal as seen in Figure 4. The springs also serve to yieldingly restrain the tilting motion.

The spring arrangement is best shown in Figures 3 and 4, wherein a vertically extending rod 117 is secured to the cantilever 20 by pivot 118. Sleeve 129, which is 'slidable -over rod 117, is pivotably secured as by pivot 121 to the outerend of bracket or arm 119, which is fixed on the upright platemember 41. A spring 123 is -mounted .over the rod 117 between the upper side of .pivot 11% and thelower end of sleeve :120. A spring 123a is mounted over the .upper side of rod 117 "between upper end of sleeve and the holding 111112.124, secured to the upper endjof rod 117. The -springs1d/23 and 1230, exerting pressure on the ends of sleeve; 120, act in opposition to one another and tend to center the whole operating head 22in an uprightposition. When the belt mouting structure is moved toward the leftlas viewed in Figure 4), spring 123a restrains the .motion. Spring 123 restrains motion in .the opposite direction. Adjustment of spring pressure.for example, to correct any unbalance of the head about trunnion vaxisplll, and/or to vary the degree ofthe centering .force-rrnay be eifected 'by the adjusting nuts 124 and 124a.

The action of the springs tends to center thev 9 The structure providing for the tilting motion of the belt as above described is an important feature in the present invention. For example, many manufacturing schedules require the heat treating or annealing of plates before the plate is ready for a finishing operation, such as polishing or grinding. In most instances, operations such as heat treating or annealing, result in a slight bow or waver in the plate, which, of course, results in a plate surface uneven in contour. In those instances where the bow or irregular contour is undesirably great, the plate may be subjected to a leveling operation, but even with a leveling operation, it is usually impossible to effect the complete removal of the bow or irregularities. Where material removed in a grinding operation must be held within close tolerances, irregular surface contours are particularly undesirable, for it is often impossible to perform a grinding operation without removing most of the irregularity and thus, the same amount of material is not removed from all portions of the surface.

The apparatus of the present invention overcomes the above difliculty, since, by means of the tilting movement, the belt accommodates itself to bows or irregular contours in plates. The belt is permitted to follow the contour of the surface and thus, to remove only the permitted tolerance in all portions of the work surface.

When such tilting is employed in combination with a cushioned surface on the working roller 39 (i. e., the surfacing 3%, Figure 3) and with uniformly maintained working pressure (as later described with reference to the controls for cylinders 80-80), there is a maximum of automatic adjustment to the unavoidable irregularities of plate contour.

The general arrangement of the hydraulic system for controlling the operation of the belt tightener-release mechanism and for controlling the engagement and disengagement of the belt with the work piece and maintaining constant engagement pressure will now be described.

As is seen in Figure 11, the belt tightener cylinders 59-59 and work contact cylinders 80-80 are supplied with hydraulic fluid through various lines and valves from hydraulic pump 28 operated by motor 27. The line labeled HF designates high pressure, while the line labeled LP designates low pressure. In the preferred arrangement, the line pressure from the pump is maintained at pressure 300 p. s. i. The oil supply is shown by numerals 144 and 144a.

As has been mentioned in connection with the description of the belt tightener-release mechanism (Figures 5 and 6), hydraulic fluid is supplied to cylinders 59-59 through fluid lines 59a-59a and 59b-59b. When high pressure fluid is supplied through lines 5911-5911, the roller 38 is moved inwardly so that the belt is loosened on its mount. When pressure is supplied through lines 5911-5917, the roller 38 is moved outwardly to supply desired tension on the belt.

Referring to Figures 1 and ll, the supply of fiuid to lines 59a and 59b is controlled by manually operated control lever 125a of control valve 125. When the valve is opened (moving the valve lever toward the left as seen in Figure 1), high pressure fluid is fed via line 126 to pressure reducer 127, which is set at 80 p. s. i. The pressure reducer 127 is interconnected with pressure reducer 128, which is set somewhat above 80 p. s. i. The pressure reducer 128 is connected with lines 5912-5922 to supply 80 lbs. pressure to the top of cylinders 59-59, which hold the roller 38 tight against the belt. The lower portion of the cylinders, connected to lines 59a-59a, is open to sump via line 129, control valve 125 and line 130. If, for any reason, pressure in the belt tightener cylinders 59-59 is greater than 80 lbs., the cylinders will discharge back to sump through pressure reducer 128 and line 131. The details of the operation of the pressure reducers and control valve are not debeyond an end of the work piece,

10 scribed because those features per-se are well-known to those skilled in that art.

To release the belt tightening mechanism, the control valve is closed by moving the valve lever to the right. In this position, the connections above described are broken and 300 lbs. pressure is supplied to the lower sides of cylinders 59-59 via lines 129 and 59a-59a. The top portions of the cylinders exhaust to sump through the pressure reducers and line 131.

As has been mentioned heretofore, the rollers 36 and 39 are adapted to be moved upwardly and downwardly to engage the belt 23 with the work piece when high pressure fluid is appropriately supplied to the work contact cylinders 80-80.

A supply of hydraulic fluid to the respective ends of the cylinders 80-80 is controlled by means of manually operated valves 132 and 133, valve 132 being used to move the belt up, while both valve 132 and 133 are used to move the belt down.

The belt is engaged with the work piece as follows: When control valve 132 is opened (by moving the valve lever 132a to the left as viewed in Figure 1), 300 lbs. pressure is fed to pressure reducer 134 via line 135. Pressure reducer 134 is set at 210 p. s. i. and is connected to pressure reducer 136 set somewhat above 210 p. s. i. Fluid at 210 p. s. i. is fed from pressure reducer 136 to the lower part of work contact cylinders 80-80 via lines 137 and 80a-80a. When control valve 133 is opened, 300 p. s .i. pressure is fed via line 139 to pressure reducer 138, which is set at 180 p. s. i. Pressure reducer 138 is connected to pressure reducer 140, which is set somewhat above 180 p. s. i. Fluid at 180 p. s. i. is fed to the top part of cylinders 80-80 via lines 141 and 8011-801). Thus, 210 p. s. i. pressure appears in the lower portion of the cylinder, whereas, 180 p. s. i. pressure appears in the upper portion of the cylinder. The weight of the rolls and associated parts has a downward force of approximately 33 p. s. i., which is exerted in the upper portion of the cylinder through piston rods 79-79 (Figure 4); thus, there is a net over-all downward force of approximately 3 p. s. i. This is the engagement pressure between the belt and the work piece, and this pressure is maintained substantially at this value during the normal sequence of operations. How this constant engagement pressure is maintained is explained below.

When an upraised portion of the plate is encountered by the belt, it forces the rollers, hence, the piston rods 79-79, upwardly and increases the pressure in the top portion of the cylinders 80-80 over 180 p. s. i. This pressure is communicated to pressure reducer via lines 80b-80b and 141, and is allowed to discharge back to sump via line 142 until the top portion of the cylinder is restored to 180 p. s. i. Thus, the 3 lbs. engagement pressure between the belt and the work piece is constantly maintained. When the machine moves the belt the whole assembly can move down under the action of cylinders 80-80, only until the adjustable stops 84-84 (Figure 4) take effect, so that no damage can be inflicted either upon the belt or upon the work bed (Figure 1) or upon any other part of the euipment.

When the belt is to be raised from the work piece, the control valve 133 is closed while the control valve 132 is left in its open position. With the control valve 133 closed, the full 210 lbs. pressure from pressure re 2 ducer 136 is fed to the lower side of the cylinders 80-80 to raise up the rolls. The upper sides of the cylinders 80-80 discharge to sump via the pressure reducers and lines 80b, 141, 142 and 108.

The general arrangement of certain of the electrical components used with the apparatus of the present invention is represented by a line diagram in Figure 12.

The belt drive motor 24 is operated at 250 volts D. C. supplied from terminal P-1 to main D. C. switch 145 to belt motor controller 146. The stop and start button 32,

the meter 31, and the rheos-tat-50 are showninterconnected to the motor control. p

The trolley bridge and pump to torsare supplied with 440 volt, 3' phase, 60 cycle'power from terminal *P-Z through main A. C. switch 147. The "trolley drive motor 17 is shown interconnected to the switch 147 through the trolley drive motor control 148. The push button'switch 35 and certain limit switches generally indicated by 149 are shown interconnectedtothe trolley control.

The limit switches'have not been shown in detail, as they are commonly known in the art. in the general arrangement ofthe 'equipment,; however, the switches are disposed near each end of the tracks IS-13 and are adapted to be actuated to stop the trolley'drive motor-17 when the trolley reaches a predetermined position on either end.

The bridge drive motors 10-40 are shown interconnected to the switch-147 "by way of the :bridge motor control 150. The push button switch '34 and-limit switch 1-51 areshow-n interconnected to the control. The limit switches are disposed on each end of the bridge tracks 77 to limit the travelover the bridge ineitherdirect-ion. The hydraulic pump motor 27 is shown interconnected to the main switch 147 by way-"of'hydraulie pump control 152. The On and Oil switch '33-for the pump motor is shown interconnected to-the control 152. The photoelectric system is supplied with power through circuit breaker 153 and step-down transformer 154. The photoelectric elements42, 43 are shown interconnected to the relays LR and RR, which are in turn connected to the belt centering solenoid S.

From the-above complete description of the equipment, including the detailed description of the fluid and electrical control systems thereof, the operation of the entire machine willnow be apparent.

Depending upon the kind of work 'piecebeing'handled, and the kind of operations to beperformed thereo ,"belts of different types may be uwd on the machine, for example belts carrying grinding material, or bufiingmaterial, or polishing materialor some other means for performing a conditioning operation upon a work piece.

Substitution f belts and replacement of worn-belts may be done with great ease-even though the belts "be of the endless type, *since-those'featuresof the machine having to do with "the mountingandstabilizing'of the operating head and thedrivin'g and contro' ling 'ofthe belt, which might otherwise interfere with dismounting or applying a belt, are all dispesedon one side of the head, leaving the otherside clear, as is evidentfromFiguresd, 2 and 4. Thus, upon retraction of roller '28, 'the beIt ZS (as seen in Figures i and 2") can he slipped off at the left side of the head 22.

The operational advantages ofthe machine particularly whentheplate ("Figures 1 and 2) is of a bowed or wavey character, 'shonld' be apparent from the detailed description, "but it maywell be pointed out in conclusion that where the plate W is a clad plate, for example,..o'f a thick "layer of carbon steel having a very thin adherent layer of some other metal, 'suclndfor example, .as nickel or stainless steelythe machine is of especial advantage in avoiding the likelihood of grinding orpo'lishing entirely through the thin layer at high spots of the plate.

l. in a machine i'or the surface conditioning of awork piece such .asa substantially fiat rotatable control roller; a rotatable contact roller; an endless belt mounted on said rollers having means for performing a conditioning operation on SZlClWOfli piece; means to rotate said belt; supporting structure'for said rollers mounted for controllable universal movement over the surface "of said work piece, the supporting structure havingineans accommodating tilting movement ofat least contact roller, independent of said universalrnovemerit, in a plane-substantially perpendicular to the surface of said work piece; and mechanism for moving the belt plate or the .like: a

back and forth along the rotational axis of said contact roller comprising two photo-electric devices oppositely disposed with reference to one edge of the belt, connected to produce first and second signals upon change in light intensity, and mechanism associated with said control roller havingmcans operative in accordance with said signals to shift the rotational axis of the control roller obliquely to the path of rotation of the belt.

2. A construction in accordance with claim 1 further including mechanism to independently move said contact roller toward and away from the workpiece whereby to engage the belt and work piece, said mechanism having means to maintain a substantially constant engagement pressure.

3. A construction in accordance with claim 2 further including a rotatable idler roller having a shaft mounted in bearings at opposite ends thereof and mechanism associated with each said bearing to swing the hearings in .an arcuate path and thereby move the roller toward and away "from the rotational path of the belt.

4. in a machine for the surface conditioning of a work piece such .as a substantially flat plate or the like: an endless rotatable belt for performing a conditioning operation on the said piece; at least one roller, the outer surface of which is adapted to contact one face of the belt to provide means for engaging said belt and said work piece; supporting structure for said roller controllably mounted for universal movement over the surface of said work piece and having mechanism acco'modating tilting motion of the roller in a plane substantially perpendicularto the work piece; resilient means to yieldably restrain said swinging movement; and means to rotate said belt.

5. A construction in accordance with claim 4-further including mechanism to yieldingly urge the roller toward the work piece-and to maintain a substantially constant selected engagement pressure between the belt and the work piece irrespective of the swinging motion of the roller.

6. In a machine for the surface conditioning of a work piece: an endless rotatable belt having means for performing a conditioning operation on said work piece; at least =two rotatable rollers providing support for said belt; means to rotate said belt; and mechanism to support said rollers and said belt 'for the belt to contact said work piece .for the conditioning operation and including means providing for yieldable tilting movement of the beltaxis of rotation relative to the work piece while the belt is being rotated and performing the conditioning operation whereby to accommodate for irregularities or bows in said work piece.

7. Aconstruction inaccordance with claim 6 in which the supportingrnechanism for t-hebelt and rollers further includes a .fluidpressure cylinder and piston connected between the roller-and the support to move the belt and rollers toward and away from the work piece and control meansconnected .to said cylinder to maintain a;substantially constantengagernent pressure vwhilethe belt and workpieceare in contact with one another.

8..In a machine for the surfaceconditioning of. a work piece such as a substantially flat plate or .thelike:

rotatable means for performing a conditioning operation.

on the work piece; mechanism providing for universal relative motion between the rotatable means and the work piece in'a plane of the work piece; andmechanisrn accommodating independent tilting movement of the rotatable means ina plane substantially perpendicular to said surface.

9. A construction .in accordance with claim 8 further including mechanism for engaging said rotatable means and said work piece having means, "for maintaining substantially constant a predeterrnined or selectedengagemcnt pressure.

1 0.1111 a work-finishing machine of the characterv described, a'head structure adapted to carry rotatable finishsubstantially parallel to thesurface ing means, a support for said structure including a cantilever member, a pivotal mounting between said head structure and said cantilever n amber, and a base on which said support is carried, the base having freedom for translational movement, whereby the finishing means may be moved over the surface of the Work for a finishing operation, said pivotal mounting providing for tilting of the head structure and the finishing means to accommodate irregularities on the surface or the Work.

11. The equipment of claim wherein said cantilever member extends into said head structure from one side thereof, and the rotatable finishing means comprises a belt traveling about the periphery of said structure,

12. The equipment of claim 10 wherein said head structure comprises spaced-apart upright side plate members interconnected by cross members, one of said plate members being apertured, and said cantilever member extends through said apertured plate to the interior of said head structure.

claim 10 having adjustment movement of said head strucof generally parallelapipedon form comprising side structures, a traveling belt disposed peripherally thereof, and a roller system for said belt, supported between said 14 structures, including an upper roller, a lower roller, two horizontally-Spaced-apart rollers at an intermediate level, means for moving the upper and lower rollers in unison to effect belt movement toward and away from a workpiece, means for mov' mountlng means providing for bodily transverse rocking of the head.

20. In a Work finishing machine of the character described: a head structure adapted to carry rotatable finishthe structure comprising spaced-apart upright through said apertured plate to the interior of said head structure; a pivotal mounting between said head structure and said cantilever member,

theh surface of the work.

References Cited inthe file of this patent UNITED STATES PATENTS 483,288 Landis Sept. 27, 1892 781,423 Hemming Jan. 31, 1905 833,710 Fletcher Oct. 16, 1906 890,463 Soules June 9, 1908 970,043 Hall Sept. 13, 1910 1,212,214 Halterbeck Jan. 16, 1917 2,195,340 Potash Mar. 26, 1940 2,220,268 Olsen Nov. 5, 1940 2,241,568 Yetter May 13, 1941 2,405,468 Talboys Aug. 6, 1946 2,445,391 Elmes et a1. July 20, 1948 2,470,221 Mott May 17, 1949 2,479,095 Boyer Aug. 16, 1949 2,558,778 Pearse July 3, 1951 2,573,220 Riedesel et al. Oct. 30, 1951 2,597,256 Murray May 20, 1952 

